A review of drinking water standards for copper and investigation of copper levels in drinking water in institutional buildings
Notice bibliographique
Résumé
Copper (Cu) has been used for centuries in the house, in industry and in agriculture. As a transition metal, it can adopt distinct redox states, which allows it to function as a catalytic cofactor in many enzymatic reactions essential to living organisms. Although copper is an essential nutrient, elevated levels of copper can be toxic. Indian Childhood Cirrhosis is a well-known epidemic of copper toxicity. Once recognized as a public health concern, daily recommended intakes were assessed at 0.3 to 3.0 mg/day for adults and at 0.1 to 2.0 mg/day for infants and young children, while the maximum safe levels for adults ranges from 0.8 to 30 mg/day and cannot be determined, due to insufficient data, for infants and young children.One of the main sources of copper ingestion is drinking water due to the extensive use of copper pipes for plumbing, although copper is more often recognized as an aesthetic concern rather than a health concern. Many countries, including Canada, have not yet established health-based drinking water standards for copper. Currently, the WHO has the most referenced health-based guideline value for copper at 2 mg/L. However, the supporting evidence for this guideline value has been questioned due to high uncertainty, insufficient data and questionable interpretation of data. Exposure studies for copper in drinking water have not considered ingestion at work or school, where the majority of waking time is spent, which may underestimate the associated health risks.First, the strength of the evidence and the science used to set the drinking water guideline values for copper is reviewed. Guideline levels, developed only for acute copper toxicity, rarely occur due to the low taste threshold of copper. There are irregularities in the reported levels of copper exposure for acute effects and the calculation of levels is not conservative. Second, copper concentrations have been measured in large institutional buildings to assess potential exposure levels. The results of the field study reveal that drinking water in these large buildings can provide a significant contribution to daily copper intakes ranging from 50% to almost 100% of the recommended daily intake values (0.7-0.8 mg Cu/day) proposed by the WHO. The field survey also shows that flushing in large building can reduce copper levels in the water by 40%. Lastly, the results confirm higher copper levels in newer or recently renovated buildings, likely due to the lack of time to develop a protective scale (due to oxidization of the copper) reducing dissolution of the pipes.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,005 | 0,010 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,002 | 0,002 |
| Bibliométrie | 0,010 | 0,012 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,002 | 0,002 |
| Science ouverte | 0,002 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».